The Service Reservation plugin provides a way for people to sign up for a specific campus, location, and service each weekend and a way to limit the number of signups for each of those locations. Visitors can select a service that they would like to attend, and the number of people attending with them. If there are still enough available spots, they'll be able to make a reservation and then will receive a confirmation email that includes the details of that reservation. Their confirmation will also include a QR code that can optionally be scanned when they arrive to validate their reservation and to record their arrival. They can also cancel their reservation if necessary.
A working instance of this plugin can be seen on the demo site here: https://compass.9embers.com/servicereservation.